1. Field of the Invention
The invention is directed to a watertight snap fastener part or press fastener part formed of an eyelet part comprising an eyelet body or of a ball part comprising a ball body, each of which has an axial opening, and a cap rivet which is fixable to a flat material, preferably in the form of a breathable or weatherproof or climate membrane,, in a watertight manner by riveting, with an elastically deformable sealing element which makes contact at the flat material and is constructed as a molded part, wherein the sealing element, being penetrated by the rivet shank of the cap rivet, has in the assembled state due to the deformation of the rivet shank a press face which is formed in an analogous manner by deformation and which surrounds the axial opening of the press fastener part and, together with a counter-face at the eyelet part or at the ball part, defines the clamping area for the flat material.
2. Description of the Related Art
In a known press fastener part of this type (DE 44 11 465 C1), the sealing element which is formed by an intricately shaped plastic disk and, at the underside of the cap rivet, forms a stationary component part of the latter has a central bore hole which is penetrated by the rivet shank, but which comprises a caplike cover, wherein the rivet shank reaches up to the latter.
When riveting with the eyelet part formed in the shape of a bar spring die, the eyelet part, after penetrating the flat material, engages in a front-side annular groove of the sealing element by a socket-like rivet shank receptacle which terminates in an annular edge that is rounded on the radial inside and forms the opening of the eyelet part, wherein the annular groove of the sealing element is coaxial to the rivet shank and adjoins the caplike cover. This annular groove is surrounded concentrically by an annular projection formed integral therewith as a front-side press face. When assembled, the rivet shank penetrates the edge of the caplike cover as well as the flat material, and the annular projection, in cooperation with the oppositely located surfaces of the eyelet part and of the sealing element, pretensions the flat material and fixes it.
In practice, it has been shown that flat material formed by a climate membrane of normal strength is adequately fixed in this press fastener part and also withstands very high tear-out forces. However, difficulties result when climate membranes of greater dimensions are used, e.g., three-ply laminates or laminates comprising a stronger woven fabric, for example, comprising loden wool.
A known construction of a watertight ring loop for footwear (DE-GM 92 16 068) in which the rivet shank end which tapers to a point is constructed in a closed manner makes use of a sealing element having a sleeve-shaped portion and an annular disk-shaped portion which extends radially outward following the sleeve-shaped portion. When the rivet shank which penetrates the sleeve-shaped portion and the footwear receiving the shoe clasps or shoe fittings is pressed with a rivet head plate, there occurs only a local pressing of the sealing element, but no substantial deformation which increases the hold, so that this known rivet pressing is also not usable for fixing a press fastener part to thicker climate membranes.
Further, a construction of an upper and lower press fastener part is known (DE 37 42 007 C) which comprises a watertight rivet cap whose shank penetrates through a flat material during pressing and is driven into a plastic part constructed in the form of a spherical part or eyelet part so as to be fixed to this flat material. This fixation method is also not suitable for fixing press fastener parts to thicker flat material.
Finally, it is also known (DE-GM 90 14 692) to assign a sealing element to a cap rivet for press fastener parts in the area between the rivet shank and underside of the rivet cap, which sealing element undergoes a deformation of varying intensity in the manner of an upset when pressed with a ball part or with an eyelet part with the flat material therebetween. The holding strength of the thicker flat material in the press fastener part is also less than desirable in this case, as would be expected.
Further, a press fastener connection is known (EP 0 401 574 A) in which the press fastener part formed by a ball part is fixed to the flat material by a cap rivet with a rivet shank which tapers to a point and is constructed in a closed manner, which rivet shank initially penetrates a sealing ring of elastic material before it penetrates the flat material and engages in the interior of a molded sheet-metal body forming the ball part and having a hat-shaped elastic plastic inserted in this molded sheet-metal body. When the rivet shank is pressed, a widening of the tip area of the rivet shank takes place and the flat material is tensioned in the area between the edge of the hat-shaped elastic plastic and the sealing ring, especially in the area of the outer zone of the hat-shaped molded sheet-metal body and that of the edge of the cap rivet. The flat material undergoes a similar clamping in the construction in which the press fastener part is formed by an eyelet part. In both cases, the holding force by which the flat material is grasped is not sufficient to fix thicker material so securely that there is no risk of tearing out.